It would be worth checking the terms & conditions. I know that Aer Lingus specifically have a bit on one of their confirmation pages which says passangers are not required to check back with the airline.
I know someone who flew from Cardiff on Saturday AM. I'm not sure whether FR contacted her, or whether she had already heard, but either way she was refunded by FR and booked herself onto an Aer Arran flight instead.
Aer Arran have taken up the route, but I think the aircraft are smaller, so the capacity on the route won't be the same.
z